fixed xpi install

backend/main.py

@@ -239,5 +239,13 @@ async def homepage_stats(_: None = Depends(require_access)):
     return await notes.get_homepage_stats()
 
 
+@app.get("/static/snotes-capture-firefox.xpi", include_in_schema=False)
+async def extension_xpi() -> FileResponse:
+    return FileResponse(
+        "static/snotes-capture-firefox.xpi",
+        media_type="application/x-xpinstall",
+    )
+
+
 # Mount static assets last so /api routes take precedence
 app.mount("/static", StaticFiles(directory="static"), name="static")